Field of the Invention
The present invention relates to a cholesteric liquid crystal mixture, a film, an IR reflection plate, a laminate, and laminated glass.
Background Art
Laminated glass with a heat-shielding film sandwiched between two glass plates is used for windshields of vehicles and for windowpanes of buildings. The heat-shielding film for use in these applications is required to be flat (not having unevenness) and fixed so that the heat-shielding film is not to be shifted in the laminated glass.
As the heat-shielding film, one that includes a liquid crystal film formed by fixing a cholesteric liquid crystal phase is known. The liquid crystal film of the type may be prepared, for example, by applying a coating liquid that contains a polymerizable cholesteric liquid crystal compound and drying it, followed by polymerization to thereby fix the cholesteric liquid crystal layer. Here, there often occurs a problem of solid deposition that contains the liquid crystal or the liquid crystal compound during coating and drying when a coating type cholesteric liquid crystal heat-shielding film is prepared. Particularly, the deposition that contains a liquid crystal brings about a trouble of optical unevenness of the obtained heat-shielding film, and is therefore desired to be solved.
As a coating liquid containing a polymerizable cholesteric liquid crystal compound, or a liquid crystal mixture in which two kinds of monomers that exhibit liquid crystallinity are blended as a liquid crystal compound, and to which a horizontal alignment agent, a polymerization initiator, a chiral agent, and the like are added (see Patent Literatures 1 and 2) is known. In these references, there is disclosed a liquid crystal mixture that uses liquid crystal compounds in a form of a mixture each satisfying the general formula (Ia) and the general formula (Ib) described therein.
Further, in a case where the heat-shielding film having a liquid crystal film obtained by fixing the cholesteric liquid crystal phase is sandwiched between the laminated glass to be used for windshields of vehicles and glass of buildings, as a method of fixing a heat-shielding film so as not to be shifted in the laminated glass, a method of heating and pressing a heat-shielding film, an interlayer film, and glass at 120° C. for 30 minutes using a sheet such as PVB (polyvinyl butyral) as an interlayer film can be used. However, the example of heating and pressing a heat-shielding film having a liquid crystal film obtained by fixing the cholesteric liquid crystal phase in the related art with such a configuration is unknown.